The present invention relates in general to an acoustic airspace collision detection system, and more particularly, to an acoustic airspace collision detection system for both piloted and unmanned aircraft that utilizes the sound generated by an approaching target to detect the direction of the target, assess the risk of collision, and automatically execute an evasive maneuver command.
Unmanned aerial vehicles (UAVs) are remotely piloted or self-piloted aircraft that can carry payloads, such as cameras, sensors, and communications equipment. UAVs perform a wide variety of intelligence, reconnaissance and surveillance missions on both the modern battlefield and in an increasing array of civilian applications. UAVs are appropriate for either hazardous missions that subject a pilot to an extreme risk of danger or extended missions that exceed or surpass the natural human endurance. Smaller UAVs offer the most operational flexibility in rapid response situations and geographic locations that lack the facilities to launch and recover aircraft.
The future of the UAV industry may be expanded to include a broader utilization in many different applications such as homeland security, law enforcement, agricultural and other civilian applications. Unfortunately such growth is hampered by certain obstacles.
For example, the utilization of UAVs in the National Airspace System (NAS) is limited to operation within predetermined flight corridors and restricted access zones. Future civilian applications of UAVs are impeded by these restrictions. These restrictions must remain in place unless there is a guarantee that UAVs can be flown with the equivalent level of safety of manned aircraft. Moreover, unmanned aircrafts must have the ability to detect and track traffic to a level equal to, or better than, the level required by the FAA order 7610.4 K “Special Military Operations” and FAR Part 91 to minimize the risk of midair collisions or other airspace incidents. Specifically, any UAV that operates in the NAS must possess an equivalent level of safety comparable to the see-and-avoid requirements for manned aircraft.
Restrictions are also placed on the use of military UAVs which are limited primarily to restricted military operational or test areas to avoid potential conflict with conventionally piloted aircraft. Similar to the operation of UAVs in civilian applications, these restrictions are necessary to avoid potential conflict with other aircraft in the geographic area. However, such restrictions may limit the effectiveness of a military mission because the UAV is prohibited from repositioning itself anywhere outside of the predetermined zones despite changing mission needs. In addition, the repeated use of limited flight corridors enables an enemy to anticipate flight paths and strategically place anti-aircraft weapons which compromises the survivability of a military UAV.
There are several different types of UAVs which are divided by class category according to size, range or flight endurance. Class I UAVs are close range vehicles having an operational range of approximately fifty kilometers. Class II UAVs have a flight duration of eight to ten hours and an operational range of two-hundred kilometers. Class III UAVs are endurance vehicles having a minimum of twenty four hours of coverage and the capability to perform multiple missions simultaneously. Prior art versions of collision detection systems, including optical and radar, have been tested on some Class III and Class IV UAVs. However, the implementation of such prior art systems has not been readily successful on smaller UAVs, such as Class I and Class II UAVs, because of the power requirements, weight, and costs of the systems.
The future growth of UAV utilization requires a UAV to be capable of detecting and avoiding all air traffic within its path of travel. The capability must interact, but not interfere, with other flight safety mechanisms of the UAV, as well as those of the approaching aircraft. Therefore, a collision detection system is needed that enables a UAV to detect any approaching aircraft in a geographic proximity, recognize the potential for a collision and initiate automatic evasive action to maintain a safe separation distance between itself and the “target” aircraft, with or without operator intervention.